The analytic structure of the QCD propagators, confinement, and deconfinement

TL;DR

This paper calculates the analytic structure of the finite-temperature Landau-gauge gluon propagator using a one-loop massive deformation of QCD, finding no signs of deconfinement and questioning the completeness of perturbative methods.

Contribution

It provides the first complete one-loop calculation of the gluon propagator's analytic structure at finite temperature using the screened massive expansion.

Findings

No signatures of deconfinement in the propagator structure

Massive perturbative methods may miss crucial dynamical information

Perturbative violation of Ward identities could be a limitation

Abstract

We present the first complete calculation of the analytic structure of the zero-spatial-momentum finite-temperature Landau-gauge gluon propagator carried out at one loop by a massive deformation of QCD perturbation theory -- the screened massive expansion -- at temperatures ranging from $T=0$ to $T\approx 3T_{c}$. We find no signatures of deconfinement in the form of meaningful changes in said structure. We argue that, beyond Euclidean space, massive perturbative methods -- including the Curci-Ferrari model -- might be missing crucial dynamical information as a consequence of the perturbative violation of QCD's Ward identities.